WO2016012374A1 - Structural element with a controllable heat-transfer coefficient u and active thermal mass - Google Patents

Abstract

The present invention relates to a structural element (1) with a controllable heat-transfer coefficient U, comprising – a first flat cavity (15), a second flat cavity (17), a flat element (9) which is arranged between the first flat cavity (15) and the second flat cavity (17), comprises at least one insulating material and has a width and height in each case corresponding to the width and height of the first flat cavity (15) and/or the second flat cavity (17), wherein the first flat cavity (15) and the second flat cavity (17) are connected to one another through the flat element (9) by means of at least a first connection line (13), and wherein the first flat cavity (15) and the second flat cavity (17) are at least partially filled with a liquid heat-transfer medium W, and – at least one pump (19) for controlling the exchange of liquid heat-transfer medium W between the first flat cavity (15) and the second flat cavity (17), which pump is arranged for the first connection line (13). The invention further relates to the use of the structural element (1) according to the invention as a wall and/or roof element in buildings or vehicles, in particular watercraft, and for conducting heat away from a first side of the structural element (1) to the second side thereof.

Description

 Construction element with adjustable heat transfer coefficient U and active thermal mass

description

The present invention relates to a structural element with controllable heat transfer coefficient U and active thermal mass and its use.

The heat transfer coefficient U in construction is a specific characteristic value of a component or building material, which in principle indicates its thermal insulation properties. The higher the heat transfer coefficient U, the worse the heat-insulating property of the component or building material.

The heat transfer coefficient U has become particularly important at the latest since the amended Energy Saving Ordinance (EnEV), which came into force in Germany in 2009, according to which the annual primary energy demand and the specific transmission heat loss of a building to be constructed must comply with certain limit values. The heat transfer coefficient U is included in the calculation of the transmission heat loss, which in turn is used in the calculation of the primary energy demand. Furthermore, the Energy Saving Ordinance prescribes limits for the heat transfer coefficient U for certain components when they are replaced or newly installed in existing buildings.

From the prior art, a variety of insulation elements is known, which are used for thermal insulation of buildings. These usually consist of one or more insulating layers of an insulating material (eg foams, foamed polymer materials). Depending on the nature of the insulating material, a protective layer is applied on the outside of such insulation elements. These insulating elements are used in particular to prevent heat leakage from the interior of a building to the outside. At the same time, a heat flow into a building can also be reduced. According to the state of the art, most of the insulating elements have fixed insulating properties, that is, the insulating property can only be regulated by varying the thickness and / or the number of insulating elements. However, this does not make it possible to react flexibly to current temperatures inside and outside a building. Due to the use of high-insulating materials, however, it is now possible that the natural outside temperature fluctuation is no longer used can be used to dissipate the heat introduced into the building during the daytime by sunlight during the night. The resulting heat accumulation increases the energy requirement for active cooling devices. There is therefore a need for an insulating element whose insulating properties are variable. In the prior art, there are first approaches to meeting this need.

Thus, DE 10 2006 024 067 A1 describes an insulating element which is particularly suitable for internal and / or external insulation of buildings. The insulating properties of the insulating element described there can be changed depending on the desired internal temperature of the building or depending on the outside temperature and / or solar radiation, in particular by changing the heat transfer coefficient U and / or the reflection properties of Dämmements themselves. For technical solution, the insulating element is provided with an insulating material , which can be changed in its position, so that the insulation used wholly, partially or substantially does not contribute to the insulation of the building. For this purpose, for example, the insulating material can be completely or partially compressed in order to release the heat flow through the insulating element completely or partially. A major disadvantage of all embodiments of the prior art is that large amounts of material must be moved or compressed, since the surface of the element must be substantially met or free of insulating material. Further, in US 4,058,109 a device for insulating and / or solar heating is disclosed. This is applied to the façade of an existing building and consists of a transparent panel, which is placed in front of a wall and thus encloses a defined space with the wall. Within the defined space, a heat absorber of a closed-cell insulating material is arranged. This heat absorber has openings, so that depending on the temperature conditions, a convection flow can form within the device described. In this way, on the one hand by the presence of the insulating material thermal insulation of the building can be achieved, while on the other hand solar radiation is used by the heat absorber to heat the trapped gas volume in the device and deliver this heat on the convection flow to a certain extent to the existing building wall.

Another approach in the prior art is described in DE 196 47 567 A1. There, a switchable vacuum insulation, in particular for use for the solar energy use, realized, with a coarse porous or coarsely structured insulation material is gas-tight enveloped and evacuated. This item can be as needed be flooded with hydrogen gas, which is within the enclosure for adsorption and adsorption of hydrogen suitable, electrically heatable getter material, which is enclosed by a heat insulating material whose thermal conductivity does not or only slightly depends on the gas pressure in this device.

Further, US 2003/0061776 A1 discloses a variable heat transfer coefficient insulating system based on an inflatable structure which responds by changing the volume to changes in the atmospheric temperature. As a result, the heat flow can be controlled.

AT 380 946 B1 discloses a so-called heat exchange wall, which consists essentially of a surrounded by a tube system insulation board in which a gaseous heat transfer medium can circulate, the circulation can be automatically locked by the special design of the tube system. For an insulating element with switchable insulation behavior is an automatic lock is not necessarily useful because the same temperature differences depending on the weather either a strong insulation or a reduced insulation make sense sense. In addition, the insulation element described in AT 380 946 B1 is constructed comparatively complicated and accordingly only bad to manufacture.

In addition, there are a number of multi-shell wall, window and roof elements, as described for example in EP 0 317 425 A2, FR 2 478 800 A1, EP 2 366 845 B1 and DE 10 2006 037 741 A1. In these elements, a change in the heat flow is achieved by either permitting or suppressing the flow of a space between the various shells with outside air. In part, the air exchange also takes place through the element with the interior. All of these approaches have the common drawback that when air flows in with outside air, dust from the air gets into the intermediate space and can lead to undesirable contamination there, which impair their optical function, in particular in the case of translucent and transparent elements. With an additional exchange of air to the interior, this hygienic problem is exacerbated in addition, as unwanted germs or pests can be carried off by the air flow.

In FR 2 798 991 A1, finally, an element is presented in which the wall is subdivided into diamond-shaped cells in which, by inclining an insulating body fitted into it, either its flow around it through a convection current is enabled or suppressed. This element is again comparatively complicated to manufacture due to the numerous segments and the non-cuboid outer shape of the individual cells. Although the insulation elements described in the prior art with, within certain limits, controllable heat transfer coefficient U have advantages over conventional insulation materials, they all bring significant disadvantages in terms of their building technical applicability with them and are sometimes extremely expensive to manufacture.

The invention is therefore an object of the invention to provide a novel construction element that minimizes the energy consumption of a building or vehicle by helping to control its heat balance. For this purpose, the largest possible controllable change of the heat transfer coefficient U is desirable.

This object is achieved in a design element of the type mentioned in a first aspect in that it has a controllable heat transfer coefficient U and is configured as follows:

Construction element (1) with controllable heat transfer coefficient U, comprising

 a first planar cavity (15),

 a second planar cavity (17),

- One between the first planar cavity (15) and the second planar

Cavity (17) arranged flat element (9) comprising at least one insulating material and its width and the height of each of the

Width and height of the first planar cavity (15) and / or the second planar cavity (17) corresponds,

 wherein the first planar cavity (15) and the second planar cavity (17) through at least a first connecting line (13) through the planar element

(9) are interconnected, and

 wherein the first planar cavity (15) and the second planar cavity (17) are at least partially filled with a liquid heat transfer medium W, and - at least one pump (19) for regulating the exchange of liquid heat transfer medium W between the first planar cavity (15) and the second planar cavity (17) arranged for the first connection line (13). In a second aspect, the above-mentioned object is achieved by the use of the construction element (1) according to the invention as a wall and / or roof element in buildings or vehicles, in particular watercraft.

A third aspect of the present invention relates to the use of the structural element (1) according to the invention for dissipating heat from a first side of the structural element (1) to its second side. The present invention is based on the finding that the heat transfer can be controlled by a design element (1) of the type described by targeted control of the flow of a liquid heat transfer medium W from the outside. The liquid heat transfer medium W represents in the present invention, an active thermal mass, which is used specifically to control the heat balance of a building or vehicle.

It has surprisingly been found that with the construction element (1) according to the invention it is also possible in a technically simple manner to significantly minimize the energy consumption of a building and thus optimally exploit the prevailing temperatures inside and outside a building. It is advantageous that according to the present invention, the heat transfer coefficient U can be controlled as required and independently of the prevailing indoor / outdoor temperatures targeted from the outside.

Thus it can be achieved by the inventive design of the construction element (1) that during the cooler night hours increased discharge of heat from the building is enabled, while at high outdoor temperatures during the daytime and at low outdoor temperatures in winter one of the regulations for adequate thermal insulation appropriate insulation effect can be ensured.

Hereinafter, the present invention will be further clarified. In a first aspect, the present invention relates to a structural element (1) with controllable heat transfer coefficient U, comprising

 a first planar cavity (15),

 a second planar cavity (17),

- One between the first planar cavity (15) and the second planar

Cavity (17) arranged flat element (9) comprising at least one insulating material and its width and the height of each of the

Width and height of the first planar cavity (15) and / or the second planar cavity (17) corresponds,

 wherein the first planar cavity (15) and the second planar cavity (17) through at least a first connecting line (13) through the planar element

(9) are interconnected, and

wherein the first planar cavity (15) and the second planar cavity (17) are at least partially filled with a liquid heat transfer medium W, and - at least one pump (19) for regulating the exchange of liquid heat transfer medium W between the first planar cavity (15) and the second planar cavity (17), which is arranged for the first connecting line (13).

In an alternative to this first aspect, the above-mentioned object is achieved by a design element (1) with a controllable heat transfer coefficient U, comprising

 a first planar cavity (15),

 a second planar cavity (17),

 a flat element (9) which is arranged between the first planar cavity (15) and the second planar cavity (17) and which comprises at least one insulating material and whose width and height are substantially equal to the width and height of the first planar cavity (15) and / or the second planar cavity (17),

 wherein the first planar cavity (15) and the second planar cavity (17) are interconnected by at least one first connecting line (13) through the planar element (9), and

 wherein the first planar cavity (15) and the second planar cavity (17) are at least partially filled with a liquid heat transfer medium W, and at least one pump (19) for controlling the exchange of liquid heat transfer medium W between the first planar cavity (15) and the second planar cavity (17), which is arranged for the first connecting line (13).

By "areal cavity" is meant in the present invention a suitably sealed volume whose width and / or height are at least an order of magnitude above its depth (i.e., thickness). Thus, a flat cavity in the context of the invention may be formed as a flat tank. This may possibly also contain bracing elements or thickness variations in the surface; corresponding constructions are known in the art.

Alternatively, the first planar cavity (15) can be replaced by a first plate (3), a frame (7) and the planar element (9) and the second planar cavity (17) by a second plate (5), the frame (7). and the sheet element (9) are defined. The planar element (9) virtually forms a partition wall between the two flat cavities (15, 17). In this case, the frame (7) of the construction element (1) according to the invention is used primarily for enclosing and mechanically stabilizing the construction element (1) and for receiving the first and second plates (3, 5), which are described in more detail below. The surface of the sheet-like element (9) is in this case tight against the liquid heat transfer medium W.

As materials for the construction of the first planar cavity (15) and / or the second planar cavity (17) are in particular polymer materials (possibly with Additives to increase the thermal conductivity), glass and metals in question. Since a high heat transfer coefficient U in the flat cavity (15, 17) filled with the liquid heat transfer medium W is desirable on the outer walls of the construction element (1), embodiments are also conceivable in which the respective outer walls of the first flat cavity (15) and / or or of the second planar cavity (17) are made of a different material than the interior of the structural element (1) facing walls (eg outer sides of metal, inside of polymer material). In addition to the heat transfer properties of the walls can be improved by material combinations for the wall materials of the first planar cavity (15) and / or the second planar cavity (17) and the mechanical stability of the structural element (1) and its fire protection properties.

The frame (7) of the construction element (1) according to the invention can also be made of metallic, polymeric (possibly fiber-reinforced) or ceramic materials or in the case of a construction element (1) according to the first and second embodiments described below and shown in Figures 1 and 3 Wood or wood-based composites be constructed. This ensures that the constructional element (1) is self-contained and thus easy to use, i. buildable, is done.

The shape of the construction element (1) can be chosen freely within wide limits and adapted to the requirements of its installation situation and / or use. A preferred embodiment is an approximately cuboidal element. But other geometric shapes are, depending on the installation situation, realized with the construction element (1) according to the invention, for example, the basic shape of a triangle, a pentagon or the like.

The construction element (1) comprises at least one planar element (9) which comprises at least one insulating material and which is arranged centrally between the first planar cavity (15) and the second planar cavity (17). The first planar cavity (15) and the second planar cavity (17) are interconnected via at least one first connecting line (13) through the planar element (9), so that an exchange of liquid heat transfer medium W between the first planar cavity (15 ) and the second planar cavity (17) is possible. In this way, heat supplied to the liquid heat transfer medium W on one side of the structural element (1) can be guided to the other side thereof. This exchange of liquid heat transfer medium W is effected by the pump (19).

It is particularly preferred if the first connection line (13) is a line with a small diameter. Such a connection line (13) with a small diameter has the further advantage that it represents a lower thermal bridge between the first planar cavity (15) and the second planar cavity (17). Advantageously, the first connecting line (13) is constructed of a thermally insulating material, for example a polymer material. As a "small diameter" is a measure of 0, 1 cm to 2 cm, in particular from 0.2 cm to 1 cm, preferred.

The planar element (9) comprises at least one insulating material, in particular of sheets of polymer foams (for example of polyurethane (PUR or PI R foams or TPU-based particle foams), polystyrene or its copolymers and melamine resins), insulating fiberboard technical or of natural origin (eg mineral wool, plant fiber mats, wood fiber boards, wool fiber boards), cavities with beds of technical or natural porous or fibrous insulation materials such as Polystyrene foam beads, cellulose and other vegetable fiber preparations, wool fibers, porous mineral granules, aerogels), insulating boards of mineral materials (eg silica airgel, foams of cementitious or gypsum-based materials, glass foams) as well as insulation boards of organic / inorganic hybrid materials, directly on the Foam produced at the location of the planar element is selected from organic, inorganic or hybrid materials. In the case of a construction element (1) of the alternative embodiment of the first embodiment described below and shown in Figure 2 either completely closed-cell and liquid-resistant materials for the sheet element (9) must be selected or this still equipped with a completely impermeable to the liquid heat transfer medium W coating become.

The expression "essentially" with respect to the height and the width of the planar element (9) in the present context means that the size of the planar element (9) is the size of the first planar cavity (15) and / or the second planar cavity (17) within the manufacturing tolerances exactly. For reasons of practical design of the construction element (1) according to the invention, however, the size of the planar element (9) can vary by up to ± 5%, without deviating from the invention. With the provided in the construction element (1) according to the invention pump (19), the flow of the liquid heat transfer medium W can be controlled specifically. Further, by stopping the pump (19), any flow can be inhibited. In this state, the heat transfer coefficient U of the structural element (1) is largely determined by the heat transfer coefficient of the sheet-like element (9). Demensprechend acts the construction element (1) with stopped, ie blocking, pump (19) as a thermal insulation. If a convection flow between the first planar cavity (15) and the second planar cavity (17) is set in motion, the heat transfer between both sides of the structural element (1) is mainly determined by this process. It has been found that already comparatively low flow rates in the range of about 1 ml / sm ² to 10 ml / sm ^{2 are} sufficient for a water-based liquid heat transfer medium W, thereby effective heat transfer coefficients U in the range of 4 W / m ² K or reach higher.

The energy necessary for the operation of the pump (19) can advantageously be collected by means of photovoltaic elements which are mounted on the side of the construction element (1) used as the outside. The generated power can be stored in appropriate on or in the construction element (1) provided accumulators, which then supply the pump (19). In this embodiment, each structural element (1) is sufficiently self-sufficient that no cabling or the like is necessary.

It is also possible to provide the pump (19) with wireless communication with an external system (eg, a building technology) to control the pump (19) as needed. For wireless communication, the necessary energy can also be supplied from the accumulator described above.

As used herein, the term "structural element" is to be understood in the context of the present invention to mean that the structural element (1) is suitable for both wall and roof surfaces. The construction element (1) is preferably self-supporting and can therefore be used independently in a shell of a building or the outer walls of a vehicle as a wall and / or roof element.

The heat transfer coefficient U (formerly also "k-value") describes a heat balance due to a temperature difference between different energy systems, thus the heat transfer coefficient U is a measure of the heat flow passage. if the temperature difference between the air on both sides of a wall is one Kelvin, the heat transfer coefficient is U. The heat transfer coefficient U is defined internationally in the standard EN ISO 6946. Its unit of measurement is W / (m ² K) The determination of exact heat transfer coefficients U The required design values for the heat transfer coefficient U are defined in the standards EN 12524 and DIN 4108-4. The heat transfer coefficient U is determined by the thermal conductivity and the thickness of the materials used, but also by heat radiation and convection at the surfaces of the component. He thus indicates the flow of heat through a single or multilayer material layer, when applied to both sides different temperatures. In the construction element (1) according to the invention, the heat transfer coefficient U can be varied between a value determined by the insulating material of the planar element (9) contained in the construction element (1) and a value determined by specific convective movements of the liquid heat transfer medium W.

In a further development of the invention, for reasons of targeted control of the heat budget, the planar element (9) has a heat transfer coefficient U of at most 0.5 W / m ² K, preferably between 0.35 W / m ² K and 0.08 W / m ² K on. It has proved to be advantageous for the targeted regulation of the flow of the liquid heat transfer medium W from the outside when the first planar cavity (15) and the second planar cavity (17) have the same capacity for the liquid heat transfer medium W. As a result, dead amounts of liquid heat transfer medium W are avoided, which would lead to an unnecessarily large thermal inertia of the system. "The same capacity" in this context means that this may vary by up to ± 5%, but in the context of manufacturing tolerances preferably the same capacity is available.

Furthermore, in a development, the liquid heat transfer medium W may comprise water and an inorganic or organic antifreeze. Water has a very good balance between heat capacity, availability and environmental compatibility for the present invention. Since the construction element (1) according to the invention is also exposed to minus temperatures during its use, a suitable antifreeze protection should be provided when using water. Examples according to the invention are Glysantin® (commercial product of BASF SE, main constituent monoethylene glycol) or water-soluble salts, in particular of the elements Na, K, Mg and Ca.

In a first preferred embodiment of the invention, the first connecting line (13) is arranged in the vertically lower region of the planar element (9) and a second connecting line (11) in the vertically upper region of the planar element (9), so that the first planar cavity (15) and the second planar cavity (17) via the first connecting line (13) and the second connecting line (1 1) are in communication so that between the first planar cavity (15) and the second planar cavity (17) via the First connecting line (13) and the second connecting line (1 1) can flow a convection flow of the liquid heat transfer medium W. The terms "vertically above" and "vertically below" are to be understood within the meaning of the present invention that they relate not only to vertically oriented structural elements (1), but also to structural elements (1), which with a certain angle to the Vertical are arranged.

"Vertically lower area" or "vertically upper area" mean that the first connecting line (13) or the second connecting line (11) in the lower or upper third, preferably in the lower or upper quarter, preferably in the lower , or upper fifth, in particular in the lower, or upper 5% of the sheet-like element (9) are arranged.

In this first embodiment, the pump (19) is used to cause a Konvektionsströmung the liquid heat transfer medium W, for example. From the first planar cavity (15) in which the liquid heat transfer medium W is heated from the inside of a building, through the second connecting line (1 1) in the second planar cavity (17), where the liquid heat transfer medium W can give off its heat to the outside, and back via the first connecting line (13) in the first planar cavity (15). In order to efficiently carry out the above-described convection flow of the liquid heat transfer medium W, i. to control specifically from the outside, it is advantageous if the first planar cavity (15) and the second planar cavity (17) are completely filled with the liquid heat transfer medium W. The phrase "completely filled" in this context refers to the fact that in practice the first planar cavity (15) and the second planar cavity (17) can not be filled to exactly 100%.

It has proven to be useful if the first planar cavity (15) and the second planar cavity (17) each have a capacity of 0.5 l / m ² to 10 l / m ² , preferably between 1 l / m ² and 5 l / m ² .

In this case, the first areal cavity (15) can have a clear dimension x and / or the second areal cavity (17) can have a clear dimension y of 0, 1 cm to 1, 0 cm, in particular 0, 1 cm to 0.5 cm, exhibit. For the purposes of the present invention, "light dimension" designates the average cross section of the respective cavity (15, 17), for example the mean inner dimension of a tank or the mean distance between a first or second plate (3, 5) and the planar element (9).

In a second alternative embodiment of the invention, the construction element (1) has only the first connection line (13) and the volume of the liquid heat transfer medium W contained in the first planar cavity (15) and the second planar cavity (17) is 50% 60% of the total Volume, which surround the first planar cavity (15) and the second planar cavity (17). Further, the above-mentioned entire volume in addition to the respective volume of the first planar cavity (15) and the second planar cavity (17) also includes the volumes which are enclosed by the first connecting line (13) and the pump (19). However, these two volumes are low compared to the volumes of the first planar cavity (15) and the second planar cavity (17).

The pump (19) is used to pump the liquid heat transfer medium W targeted by the first planar cavity (15) through the first connecting line (13) in the second planar cavity (17). The volume of liquid heat transfer medium W must be dimensioned in any case so that either the first planar cavity (15) or the second planar cavity (17) and the connecting line (13) can be completely filled. In operation of the construction element (1) according to the invention of the second, alternative embodiment, the liquid heat transfer medium W is alternately completely either in the first planar cavity (15) or in the second planar cavity (17). The liquid heat transfer medium W used in the second alternative embodiment also comprises water. The addition of an inorganic or organic antifreeze is not provided in this case, since the use of this structural element (1) at minus temperatures the liquid heat transfer medium W is pumped to the side of the structural element (1), which faces a building or vehicle, i. on the "warm" inside. On the other hand, the presence of inorganic or organic antifreeze in the liquid heat transfer medium W is not a hindrance to the second alternative embodiment. The liquid heat transfer medium W, which, for example, in the first planar cavity (15) has been heated from the inside of a building, is pumped into the second planar cavity (17), where it can release its heat to the outside again. The first planar cavity (15) is then emptied of the liquid heat transfer medium W except for unavoidable but negligible amounts.

It has proven to be useful if in the second alternative embodiment in the vertical upper region of the sheet-like element (9) a pressure equalization line between the first planar cavity (15) and the second planar cavity (17) is provided, so that the gas volume over the liquid heat transfer medium W when it is pumped into the first planar cavity (15) or the second planar cavity (17) in the other two-dimensional cavity (15, 17) can escape. The pressure equalization line is preferably designed that no transfer of liquid heat transfer medium W takes place, for example. By a check valve.

In this second embodiment, it has proven to be expedient if the first areal cavity (15) and the second areal cavity (17) each have a capacity of between 1 l / m ² and 100 l / m ² , preferably between 5 l / m ² and 40 l / m ² . Capacities in this area represent a good compromise between sufficient thermal storage capacity of the liquid heat transfer medium W received therein and a manageable weight of the structural element (1) of the second, alternative embodiment.

In this case, the clear dimension x of the first planar cavity (17) and / or the clear dimension y of the second planar cavity (17) may each be 0.5 cm to 10.0 cm, in particular 0.5 cm to 4.0 cm ,

In a further development of the second embodiment, in each case a film chamber system is provided in the first planar cavity (15) and / or the second planar cavity (17), which is buoyant on the liquid heat transfer medium W and at first of the liquid heat transfer medium W emptied first planar cavity ( 15) or second flat cavity (17) completely fills it in fully unfolded state.

The film chamber system has, in particular on its underside, a float element which floats on the surface of the liquid heat transfer medium W. At its upper side, it is attached to the upper inner side of the first planar cavity (15) or the second planar cavity (17) of the structural element (1). If the liquid heat transfer medium W is pumped from one planar cavity (15, 17) into the other, the film chamber system unfolds, so that it completely fills the volume of the respective empty flat cavity (15, 17) when fully deployed, and thus an optionally occurring convection of the contained gas volume prevents. As a result, an even lower heat transfer coefficient U of the entire system is achieved. In addition, the film chamber system may be provided with a reflective surface to achieve a further improvement of the insulating effect.

It has proven to be advantageous for the first and second embodiments when the first planar cavity (15) and / or the second planar cavity (17) is / are structured on the surface in three dimensions. Through this three-dimensional patterning, the effects of the conventional flow in the first embodiment and the heat flow in the second embodiment can be conducted more effectively. In addition, the mechanical stability of the respective planar cavity (15, 17) can be improved. When using a Foil chamber system, the structuring must be such that still the folding and unfolding of the floating film chamber system is possible.

The planar element (9) can in particular be formed from a mineral, metallic, polymeric and / or bioorganic material. This is advantageous if the construction element (1) should not be used as a translucent component, but is exposed to increased mechanical stresses (metallic material, fiber-reinforced polymer) or purely for thermal insulation (mineral and / or polymeric material). Furthermore, it is possible with this embodiment, also ecologically particularly compatible design elements (1) to create (bio-organic materials). The material used may be open-pored or closed-cell.

In addition, as far as the outer surfaces of the first planar cavity (15) or the second planar cavity (17) of the structural element (1) have been suitably coated or otherwise modified so as to reflect the incident solar radiation directly or diffusely, it is Construction element (1) during the day a particularly low heating by solar radiation instead.

In a second aspect, the present invention relates to the use of the construction element (1) described above as a wall and / or roof element in buildings or vehicles, in particular in watercraft. In the following, the invention annex buildings is explained, but in principle also applies to vehicles, especially watercraft.

A third aspect of the present invention relates to the use of the structural element (1) according to the invention for dissipating heat from a first side of the structural element (1) to its second side. In particular, this aspect can be used to purposely dissipate heat from a building to the outside during the warmer months during cooler night hours or during individual cooler days, i. to effect a targeted cooling of the building. In this case, the present invention can be applied not only to apartments and offices to create a pleasant climate, but also to rooms in which a lot of heat is generated by machines, for example, factory buildings or server rooms.

But also in the opposite direction, the invention can be used, for example. On sunny days in the cold season on the outside of a building on the construction element (1) of the present invention absorb heat and initiate targeted heating for heating in the building. Therefore, in the above-described use, the thermal capacity of the liquid Heat transfer medium W are used in particular as a thermal mass. The thermal capacity, ie the thermal storage capacity (also called thermal mass), which is available for these purposes, is greater, the larger the amount of liquid heat transfer medium W contained in the element. However, any increase in this amount is not meaningful for reasons of weight and increasing thermal inertia of the amount of liquid.

Furthermore, the present invention relates to the use of the construction element (1) according to the invention, in particular according to the second embodiment, wherein the liquid heat transfer medium W is coupled against external heat or cooling reservoirs. Such reservoirs can be cold groundwater or the (cold) drinking water network or local hot water tanks.

Other features, advantages and applications will become apparent from the following description of the preferred, the invention but not limiting embodiments and the figures. All the described features alone or in any combination form the subject matter of the invention, also independent of their summary in the claims or their relations. Show it:

Fig. 1 is a schematic representation of a construction element 1 in a first

 Embodiment of the invention,

Fig. 2 is a schematic representation of a development of a

 Construction element 1 in a first embodiment of the invention and

Fig. 3 is a schematic representation of a construction element in a second

Embodiment of the invention. Figure 1 shows a first embodiment of a construction element according to the invention 1. The construction element 1 is formed by a first planar cavity 15 and a second planar cavity 17 with a sheet-like element 9 therebetween. The flat cavities 15, 17 are here designed as flat tanks, which may for example consist of a metal on the outside and a coating of a polymer material on the inside. Through the planar element 9 leads in the lower region, a first connecting line 13 with pump 19 provided therein in the upper region, a second connecting line 1 1 is provided. The liquid heat transfer medium W, which is not provided with a reference numeral here, is hatched in the two-dimensional cavities 15, 17. Representative of all figures are given in Figure 1, the clear dimension x of the first planar cavity 15 and the clear dimension y of the second planar cavity 17

To generate a convection flow of the liquid heat transfer medium W, this is pumped by the pump 19 targeted by a flat cavity 15, 17 in the other. Depending on the desired mode of action is either pumped from the inside heated liquid heat transfer medium W on the outside of the structural element 1, for example, to cool a building. Conversely, heat from outside the building can be fed inwards. If no replacement is desired, the pump 19 is selectively stopped and thus prevented any convection flow. The construction element 1 acts in this case as insulation.

FIG. 2 shows a development of the first embodiment. Here, the structural element 1 is constructed by a frame 7 which forms four sides of the structural element 1, namely top and bottom as well as the side surfaces. In the illustration of Figure 2, the frame 7 is shown in section only above and below. In the frame 7 are two opposite plates 2, 3, 5, i. a first plate 3 and a second plate 5, arranged. Between the two plates 3, 5, a planar element 9 is arranged so that it closes laterally, above and below with the frame 7, respectively. Furthermore, the planar element 9 is arranged with a clear dimension x to the first plate 3 and with a clearance y to the second plate 5. Through the planar element 9, a first connecting line 13 with pump 19 provided therein also leads here in the lower area. In the upper area, a second connecting line 11 is provided. The liquid heat transfer medium is shown for the sake of clarity not hatched.

On both sides of the sheet-like element 9 and through the connecting lines 1 1, 13, a convection flow can form. Thus, heat can be transferred from the second plate 5 to the first plate 3 by the convection flow.

According to another development, which is not illustrated, active convection elements can be integrated into the first planar cavity 15 and / or into the second planar cavity 17. By "active convection elements", for example, small rotors are understood which support the formation of the convection flow or the circulation of the liquid heat transfer medium and maintain it. As a result, in particular the switching stroke between the higher temperature side and the lower temperature side is increased.

Figure 3 shows schematically a construction element 1 according to the invention according to a second embodiment. In this, the first planar cavity 15 and the second planar cavity 17 is connected only via the first connecting line 13, in which a pump 19 is arranged. The illustration shows a state in which the first planar cavity 15 is filled only slightly with the liquid heat transfer medium W shown here hatched again, while the second planar cavity 17 is largely filled with it. FIG. 3 thus shows a state during the pumping of the liquid heat transfer medium W from one surface cavity 15, 17 into the other. The non-hatched areas of the first planar cavity 15 and of the second planar cavity 17 represent in FIG. 3 free volume, which is usually filled with a gas.

As is clear from Figures 1 to 3, in reversal of the known from the prior art effect, the construction element 1 of the invention can be used in particular to dissipate heat from buildings. This can be advantageous, for example, in the warm season. Furthermore, the application of the construction element 1 according to the invention for heat dissipation from industrial buildings is conceivable.

Depending on the installation situation of the construction element 1 according to the invention, this can be carried out either vertically or inclined. In this way, both wall surfaces and sloping roof surfaces can be formed. The angle of the sloping roof surfaces to the vertical is between 0 ° and 90 °, preferably between 5 ° and 60 °. Despite the oblique position of the construction element 1 according to the invention, the principle of the specifically controllable heat transfer coefficient U is retained, i. the control by targeted control of the internal convection flow. This also applies to the use of the construction element 1 according to the invention in flat roofs.

The construction element 1 according to the invention can therefore be used as a wall and / or roof element in a shell, without having to provide further wall elements or roof elements. Of course, the construction element 1 according to the invention can also be used as a classic insulating element for placement on a facade.

A concrete example of the first embodiment is given in tabular form below:

When the pump 19 is stationary, there is insulation.

When the pump 19 is switched convective heat transport takes place:

about 4.2 J / (ml K),

Flow rate 1 ml / (sm ² ) (about 3.6 l / (hm ² )): Ui = 4.2 W / (m ² K)

Flow rate 10 ml / (sm ² ): Ui = 42 W / (m ² K)

Water volume on each side: about 2 l characteristic residence time for "fast" flow: about 5 min

characteristic heat diffusion length in this time: (D _th = 0.134 e-6 m ² / s): 9 mm possible upper U-value in the system: 5.3 W / (m ² K)

thermal mass of water (4 l / m ² ): about 4.7 Wh / m ² K

worin h_se den Wärmeübergangskoeffizienten auf der Außenseite bzw. h_si den Wärmeübergangskoeffizienten auf der Innenseite bezeichnet. The equation holds

where h _se denotes the heat transfer coefficient on the outside and h _si the heat transfer coefficient on the inside.

In accordance with DIN 4108, the following values are usually used:

h _se = 25 W / m ² K,

h _si = 8 W / m ² K

Hereinafter, a concrete example of the second embodiment is given by way of example:

When the pump 19 is stationary and water on the inside of the structural element 1 is present, the internal thermal mass is 23 Wh / m ² K.

With the pump 19 stationary and water on the outside of the structural element 1, insulation prevails, the internal thermal mass is 23 Wh / m ² K.

Time constant for pumping <30 min (at 12 ml / s)

 Thermal time constant <1 h due to convection inside the reservoir tank.

Possible operating modes a) simple facade collector on cold days with good wall irradiation b) multiple circulation of the thermal mass during the night in the cooling season, which corresponds to a switchable U value> 5 W / m ² K (where the U value is here temporal mean over the effect of the element over a period of several hours must be understood) The present invention offers a number of other possibilities for tempering buildings. Thus, the liquid heat transfer medium W at least partially filled cavities 15, 17 can be coupled against external heat or cold reservoirs, for example against cold groundwater or the drinking water network or against local hot water tanks. In this case, a networking between different locations of the building at predetermined levels can be made.

Furthermore, the energy storage capacity of the construction element 1 according to the invention can also be coupled with other energy sources, in particular the public power grid, in the sense of a "smart grid" in order to enable energetically optimal operation of "thermally active" household applications such as dishwashers or washing machines. For this purpose, a control software is necessary, which calculates from the current energy supply in the public power grid and the thermal energy stored in construction elements 1 according to the invention, when the operation of a household appliance is the most sensible, which requires partial electrical and partial thermal energy. Furthermore, it is possible to provide the not inconsiderable amounts of liquid heat transfer medium W, in particular in the case of water, as an emergency reserve for fire protection. For example, rupture disks can be provided in the cavities 15, 17, which release the liquid heat transfer medium W into the building when a critical temperature is reached.

LIST OF REFERENCE NUMBERS

I construction element

3 first plate

 5 second plate

 7 frames

 9 flat element

 I I second connection line

13 first connection line

 15 first planar cavity

 17 second planar cavity

 19 pump

x light dimension of the first planar cavity 15 y light dimension of the second planar cavity 17th

Claims

claims 1 . Construction element (1) with controllable heat transfer coefficient U, comprising  a first planar cavity (15),  a second planar cavity (17),  a flat element (9) arranged between the first planar cavity (15) and the second planar cavity (17), comprising at least one insulating material and whose width and height are each the same Width and height of the first planar cavity (15) and / or the second planar cavity (17) corresponds,  wherein the first planar cavity (15) and the second planar cavity (17) are interconnected by at least one first connecting line (13) through the planar element (9), and  wherein the first planar cavity (15) and the second planar cavity (17) are at least partially filled with a liquid heat transfer medium W, and  at least one pump (19) for controlling the exchange of liquid heat transfer medium W between the first planar cavity (15) and the second planar cavity (17), which is arranged for the first connecting line (13). 2. Construction element (1) according to claim 1, wherein the sheet-like element (9) has a heat transfer coefficient U of at most 0.5 W / m ² K, preferably between 0.35 W / m ² K and 0.08 W / m ² K. 3. Construction element (1) according to claim 1 or 2, wherein the first planar cavity (15) and the second planar cavity (17) have the same capacity for the liquid heat transfer medium W. 4. Construction element (1) according to one of claims 1 to 3, wherein the liquid heat transfer medium W comprises water and an inorganic or organic antifreeze. 5. Construction element (1) according to one of claims 1 to 4, wherein  the first connecting line (13) is arranged in the vertically lower region of the flat element (9) and a second connecting line (1 1) is arranged in the vertically upper region of the planar element (9), so that the first planar cavity (15) and the second planar cavity (17) via the first connecting line (13) and the second connecting line (1 1) are in communication, that between the first planar cavity (15) and the second planar Cavity (17) via the first connecting line (13) and 5, the second connecting line (1 1) a convection flow of the liquid heat transfer medium W can flow. 6. Construction element (1) according to one of claims 1 to 5, wherein the entire volume of the first planar cavity (15) and the second planar 10 cavity (17) is completely filled with the liquid heat transfer medium W. 7. Construction element (1) according to one of claims 1 to 6, wherein the first planar cavity (15) and the second planar cavity (17) each have a capacity of 0.5 l / m ² to 10 l / m ² , preferably between 1 l / m ² and 5 l / m ² , 15 have. 8. Construction element (1) according to one of claims 1 to 3, wherein in the first planar cavity (15) and the second planar cavity (17) contained volume of the liquid heat transfer medium W 50% to 60% of 20 total volume occupies that enclose the first planar cavity (15) and the second planar cavity (17). 9. construction element (1) according to one of claims 1 to 3 and 8, wherein the first planar cavity (15) and the second planar cavity (17) each one 25 capacities between 1 l / m ² and 100 l / m ² , preferably between 5 l / m ² and 40 l / m ² , have. 10. Construction element (1) according to one of claims 1 to 3, 8 and 9, wherein in the first planar cavity (15) and / or the second planar cavity 30 (17) each a film chamber system is provided which is buoyant on the liquid heat transfer medium W and completely fills in fully deflated by the liquid heat transfer medium W first flat cavity (15) or second planar cavity (17). 35 1 1. Construction element (1) according to one of claims 1 to 10, wherein the first planar cavity (15) and / or the second planar cavity (17) is structured on the surface in three dimensions / are. 12. Use of the construction element (1) according to any one of claims 1 to 1 1 40 as a wall and / or roof element in buildings or vehicles, in particular water vehicles. 13. Use of the construction element (1) according to one of claims 1 to 1 1 for dissipating heat from a first side of the construction element (1) to the second side thereof.  5  14. Use of the construction element (1) according to claim 13, wherein the thermal capacity of the liquid heat transfer medium W is used as a thermal mass. 10 15. Use of the structural element (1) according to one of claims 1 to 3 and 8 to 1 1, wherein the liquid heat transfer medium W is coupled to external heat or cooling reservoirs.